The tap water in most homes contains various substances which may be hazardous to health. This is because many carcinogens, toxic chemicals and poisonous heavy metals from industrial waste water effluents, run-off from farms, animal feed lots and city streets, and waste water effluents from homes and municipal sewage treatments systems find their way into our drinking water supplies. Many of these dissolved substances cannot be removed by currently used methods of water treatment and purification. Thus, many of the water supply systems in the United States fail to meet the present U.S. Public Health Service drinking water standards. Even if some means were found for removing dissolved chemicals from the water at the water treatment plant, the pure water produced could not be delivered in pure form to the home through existing plumbing. Poisonous cadmium, for example, may be picked-up in transit from galvanized pipe and plumbing, toxic copper from copper plumbing, and poisonous lead from lead plumbing.
While various types of bottled water are sold for drinking purposes, many fail to meet the standards of the U.S. Public Health Service for drinking water. Thus, safe drinking water is not necessarily obtainable through the purchase of water, either from a water system or bottled water.
One satisfactory way of providing safe drinking water is to produce distilled water in the home by means of a home distiller. This removes virtually all of the undesired substances from the water such as organic materials, toxic chemicals and poisonous heavy metals.
One objective of the present invention is to provide an adequate storage reservoir for the distilled water produced which will keep the water from becoming contaminated with airborne substances such as microorganisms and viruses. Another objective is to provide a distillation apparatus which can be easily and conveniently dismantled for cleaning and maintenance. A third objective is to provide a distiller that can easily be kept clean of "scale" which is a particularly severe problem in hard water areas. A fourth objective is to provide a fully automatic water distiller that can be operated by technically unskilled persons such as the average housewife. A fifth objective is to provide a home water distiller that can be conveniently mounted on or in a cabinet or on a wall. The wall or cabinet mounting should not only get the distiller off the counter top but should facilitate cleaning and maintenance. A sixth objective is to provide a fully automatic home water distiller that produces laboratory quality pure water.
The present invention satisfactorily solves the foregoing objectives by providing an automatic water distillation apparatus designed primarily for home use, although it can be employed for laboratory use.
In accordance with the invention, the fully automatic water distillation apparatus has a self-contained distillate storage reservoir which is an integral part of the condensing system. Thus, the storage reservoir is automatically steam sterilized with each cycle of operation. This protects the user against airborne organisms, viruses and other contaminants without the need for additional attention or care.
The invention also provides a modular type distillation apparatus that facilitates maintenance and cleaning. This is accomplished by a self-contained storage reservoir serving as the body of the apparatus. The preheating and condensing module is removably inserted into the top part of the storage reservoir module and the evaporator module is removably connected to the bottom of the storage reservoir module.
The invention also provides a distillation apparatus that can easily be kept clean of scale. This is accomplished by coating the surfaces of the evaporator with scale resistant substances such as flouroplastic, eg TEFLON, by using scale resistant materials such as CPVC for feedwater tubing and fittings, and by mounting the electrical resistance heating element to the external surface of the evaporator.
The invention also provides a fully automatic distillation apparatus that can be operated by the average domestic user who has minimal technical skills. This is accomplished by a float operated switch that is activated by the water level in the storage reservoir, by a thermostatically controlled water inlet valve that turns the supply water to a preheating and condensing coil on and off when steam is available for heat exchange with the supply water, by a water flow control fitting that provides a constant rate of water flow to the preheating and condensing coil regardless of fluctuations in line pressure and by a water level control well that maintains a constant water level in the evaporator.
The distillation apparatus can be conveniently mounted on or in an existing cabinet or on a wall. This is accomplished by securing the storage reservoir module to the wall or cabinet by a mounting bracket. To facilitate cleaning, the evaporator is removably connected to the bottom end of the storage reservoir module.
The fully automatic water distillation apparatus is designed for home use but also produces pure laboratory quality distilled water. This is accomplished by preheating the water to drive off volatile gases and low boiling substances and providing a venting means through which these substances can escape, by providing a relatively long insulated vapor column which prevents excessive heat loss from the rising steam and which encloses a spiral baffle on which high boiling substances that inadvertently escape the evaporator may condense and drain back into the evaporator, and by providing a further baffling apparatus that prevents water droplets from being carried by the column of rising steam into the condensing apparatus and which also provides sufficient surface area on which the droplets can condense.
This invention relates to a water distillation apparatus having an evaporator module including an evaporator means disposed within a casing. A distillate storage reservoir module is removably connected to the evaporator module. An insulated vapor column is disposed within and as an integral part of the storage reservoir module. A condensing and preheating module is removably carried by the storage reservoir module, and a water inlet and flow control valve and fitting are connected to a preheating and condensing coil.
Cold water from the household supply enters the preheating and condensing coil through the water inlet valve and flow control fitting. The incoming cold water condenses the steam that impinges upon the condensing side of the coil, while the steam preheats the feedwater flowing through the coil before it leaves the coil and enters the evaporator through the feedwater tube. Steam from the evaporator rising through the vapor column activates the thermostatically controlled valve. The valve opens allowing water to flow through the preheat and condensing coil into the feedwater tube. A portion of the water flowing through said tube enters the evaporator. The excess water is discharged through the drain tube into the household sewer line. The level of the water in the evaporator is maintained by means of a water level control well disposed in the side of said evaporator. The rate of flow of water flowing through the preheat and condensing coil is regulated by means of the flow control fitting. The steam, rising from the evaporator through the vapor column, condenses on the condensing side of the preheating and condensing coil and is collected in the self-contained storage reservoir. When the storage reservoir is full, a float activated switch electrically disconnects the electrical resistance heating element. If approximately one liter of water is withdrawn from the reservoir, the heating element is reactivated. If the cold water supply is interrupted, a high temperature circuit breaker electrically disconnects the heating element. The circuit breaker must be manually reset before the heating element will operate.
In a modified embodiment of the invention, the preheat and condensing coil is replaced by a preheat chamber defined by a condensing surface plate sealingly mounted around its periphery to the wall of the storage module. An inverted U-shaped discharge tube extends from within the preheat chamber to the feedwater tube, and thence to the evaporator chamber. The apex of the discharge tube is at or above the level of the top wall of the preheat chamber, such that the preheat chamber must be full to feed water to the evaporator chamber due to water inlet pressure. By maintaining the preheat chamber full at all times, evapporation is minimized, thereby reducing or eliminating accumulation of scale. A spiral vent plate or baffle extends downwardly through the feedwater tube for enhanced venting of volatile gases and low boiling substances in the feedwater.